1. Technical Field
The invention relates to a surveillance camera apparatus and a surveillance camera system, which use plural kinds of cameras in combination so as to clearly capture an image of a moving object, which is a surveillance target within a wide surveillance area.
2. Description of Related Art
A surveillance camera apparatus for security on a coastland or a borderland is required to have a wide surveillance area. In this case, a camera-to-subject distance to be kept under surveillance reaches several kilometers to 10 or more kilometers. Also, it is desired that a surveillance camera apparatus for surveiling a road such as a general road and a highway has a camera-to-subject distance at least several tens to several hundreds meters. It is necessary that such a surveillance camera apparatus has a function of identifying a moving object, which is regarded as a surveillance target, in an early stage and a function of surveiling the moving object while tracking the moving object. According to the related art, a surveillance camera apparatus used for such a purpose captures a wide surveillance area while scanning the area with one camera being panned or tilted. Therefore, it cannot be said that the surveillance camera apparatus has sufficient reliability in surveillance of a transient phenomenon or a moving object.
Another system divides a surveillance area into a plurality of divisions, and allocate plural cameras to the divisions respectively for capturing. However, each camera is required to have a image-capturing lens with a focal length long enough to identify distant moving objects exactly. Such cameras naturally have narrow angles of view. Therefore, the number of divisions has to be increased and the cameras have to be provided for the divisions respectively in order to cover a wide surveillance area. As a result, the cost increases on a large scale, and the apparatus as a whole increases in size inevitably.
Of surveillance camera apparatuses for security, which serve as a part of measures for security, for example, JP Hei. 9-55930 A and JP 2004-15516 A combine a fixed wide-angle camera and a zoom camera having an optical axis whose direction can be changed desirably by a motor-driven camera platform and keep capturing a target moving object under surveillance by a zoom camera after the surveillance target is identified.
The surveillance camera apparatus according to JP Hei. 9-55930 A always captures the whole surveillance area by the wide-angle camera placed fixedly, and displays a thus-captured image on a monitor. When an operator operates a mouse on the monitor screen so as to specify a specific area on the screen, the optical axis of the zoom camera is directed to the specified area so as to capture the specified area with a high magnification. On the other hand, the surveillance camera apparatus according to JP 2004-15516 identifies a moving object in a captured screen based on image data captured by the wide-angle camera while the position coordinates of the moving object are calculated continuously. The optical axis of the zoom camera is directed in a direction corresponding to the calculated position coordinates so as to capture the moving object in an automatic tracking system.
The surveillance camera apparatus according to each reference is used in order to watch whether a moving object such as a suspicious person has intruded near or into a building. It is therefore satisfactory that the wide-angle camera can identify a moving object within a camera-to-subject distance ranging from about several meters to about several tens of meters. Accordingly, an image of the moving object having a certain size is contained in an image captured by the wide-angle camera. Thus, a specific area can be specified by manual operation as in the apparatus disclosed in JP Hei. 9-55930, or tracking information for the zoom camera can be acquired based on the image captured by the wide-angle camera as in the apparatus disclosed in JP 2004-15516.